Bayawak (Bah-yah-wahk) or monitor lizards are all over the forested areas of Palawan. This one is about 4 feet and 6 inches long. Unfotunately when I clicked on the shutter the forked tongue has retracted. It can move fast on the ground. This one was stopped for a while because the guide tried to stop it by pulling its tail.
Monitor lizards are considered to be the most highly developed lizards, possessing a relatively rapid metabolism for reptiles, several sensory adaptations that benefit the hunting of live prey, and a lower jaw that may be unhinged to facilitate eating large prey animals. Monitors are carnivorous and will devour anything they are capable of dismembering and gulping down. Species which live in or near water will readily eat fish. Many species hold their heads erect on their long necks, which gives them the appearance of being alert. They intimidate predators by lashing out with their tails, inflating their throats, hissing loudly, turning sideways, and compressing their bodies.
They are mostly terrestrial, but many are agile climbers and good swimmers. The tail is somewhat compressed in tree dwellers, very compressed in semiaquatic monitors.
Information were taken from Wikipidia and Google.